Utilizing an experimental design and scale up of a wet fluidized bed agglomeration process, to produce novel carbon agglomerates and tablets

Abstract

Wet granulation and agglomeration processes are widely used in the pharmaceutical industry. This study was performed, aimed at developing a systematic approach to scale up a carbon agglomeration process from 10 kg to 100 kg. The goal was to achieve similar granule sizes with different granulators during production. The formulation of the powder bed at the start of the agglomeration process was based on carboxymethyl cellulose as a binder, carbon and peroxide powder. In the first production step this composition was used to produce agglomerates. Agglomerates were evaluated for particle flow and particle size. Finally, compressive strength of cylindrical carbon tablets was measured, following compression with a five cavity mechanical press. It was found that the agglomeration liquid quantity, the inlet air flowrate and the droplet size distribution play a fundamental role in the upscaling process. Therefore, these mentioned parameters had to be systematically scaled up for different batch sizes in order to achieve similar particle growth in the different fluidized bed sizes. A previous study, through a design of experiments has shown that a target geometric mean granule size of around 575 µm is desirable in terms of the granules flowability and granules properties. For example: The compressive strength of the carbon tablets. Furthermore, a DoE for the spraying parameters was applied to compare the final tablet properties. The scale up process from a laboratory to a production size granulator, was successfully performed. This was based on the granule’s properties and the mechanical stability of the carbon tablets.